Breast cancer is a complex disease with many contributing factors. Some of these factors, such as age, family history, genetics, and gender, cannot be controlled.

However, there are factors that individuals can control, which include smoking, not exercising, being overweight, and their diet. Some researchers maintain that diet could be responsible for 30 to 40 percent of all cancers.

Breast cancer can start in different places, grow in different ways, and require different kinds of treatment. Just as certain cancers respond better to certain treatments, certain cancers respond well to specific foods.

The following foods are considered part of a healthful diet in general, and they may help to prevent the development or progression of breast cancer:

A study of more than 91,000 women found that following a diet comprising mainly plants could cut the risk of developing breast cancer by 15 percent. The Ida & Joseph Friend Cancer Center recommend between 8 and 10 servings of fruits and vegetables per day.

Along with their other benefits, fruits and vegetables are rich in flavonoids and carotenoids, which are linked to a host of medical benefits. Studies have found the following fruits and vegetables to be good for preventing breast cancer:

Dark, green, leafy vegetables

Peppers

Tomatoes

Eggplant

Citrus fruit

Carrots

Broccoli

Kale

Onions

Apples

Pears

Peaches

Strawberries

Dietary fibre

Although research into dietary fibre and its effect on breast cancer is currently inconclusive, several studies suggest that it can help protect against the disease. Because fibre supports the digestive system and regular elimination of waste, it helps the body to get rid of toxins and limits the damage they can do.

Whole grains and legumes also contain antioxidants, which can help to prevent many diseases. Eating more fibre-rich legumes, such as lentils, has also been associated with a reduced risk of breast cancer. The Ida & Joseph Friend Cancer Center recommend 30 to 45 grams of fibre per day.

Good fat

Fat might seem an unlikely candidate for a list of good foods for breast cancer prevention, but polyunsaturated and monounsaturated fats have been called the “good fats.” They are found in olive oil, avocados, seeds, and nuts.

Additionally, omega-3 fatty acids, found in cold water fish such as salmon and herring, have been linked to a reduced risk of breast cancer. Many experts recommend a diet in which around 20 to 30 percent of daily calories are from fat, with no more than 8 percent of total calories from saturated fat.

Soy

Extensive research over the past 25 years has identified soy as an extremely healthful food source, rich in protein, healthy fat, vitamins, and minerals, but low in carbohydrates. In addition to reducing the risk of breast cancer, soy is also reported to reduce low-density lipoprotein, or “bad cholesterol,” and lower the risk of heart disease.

Soy is found in foods such as:

Tofu

Tempeh

Edamame

Soy milk

Soy nuts

Benefits of these foods

Some studies have found that the health benefits of omega-3 fatty acids found in some fish might be due to its ability to reduce inflammation, a possible contributing factor for breast cancer.

estrogen from interacting with breast cancer cells, so eating a high-fibre diet can support this process and accelerate the elimination of estrogen.

Beta-carotene, found in vegetables including carrots, has been associated with a lower risk of breast cancer. Scientists speculate that this may be because it interferes with the growth process of cancer cells.

List of foods to avoid and why

As scientists continue to explore the impact of different foods on the risk of breast cancer, people are generally advised to cut down on alcohol, added sugar, fat, and red meat.

Alcohol

Studies have identified a link between regular alcohol consumption and an increased risk of breast cancer. Breastcancer.org report that alcohol may increase estrogen levels and cause damage to DNA cells. They also note that women who drink three alcoholic beverages per week increase their risk of developing breast cancer by 15 percent. The risk goes up by around 10 percent with each additional drink per day.

Researchers at the University of Texas MD Anderson Cancer Center have found that when mice eat a diet as rich in sugar as the typical American diet, they are more likely to develop mammary gland tumors, similar to breast cancer in humans. In addition, these tumors are more likely to spread, or metastasize.

Fat

Studies suggest that not all fats are bad. While fat from processed foods is linked to an increased risk of breast cancer, fat from fruits and vegetables is associated with a decrease in risk.

Trans fats have now been associated with an increased risk of breast cancer and should be avoided. Trans fats are most commonly found in processed food such as fried foods, some crackers, donuts, and packaged cookies or pastries.

Red meat

Although research is on-going, some studies have found a link between red meat and a greater likelihood of breast cancer, especially if the meat is “well done.” In addition, processed meats and cold cuts tend to be high in fat, salt, and preservatives and are not considered effective food for breast cancer prevention.

According to the Ida & Joseph Friend Cancer Resource Center, the following may also help the body to protect itself against breast cancer:

Vitamin D from regular exposure to sunlight may help. Vitamin D is also found in foods such as eggs, cold-water fish, and fortified products. Consult a doctor to check levels and if they are low, consider a supplement.

Green tea is associated with a number of beneficial health effects, including strengthening the immune system and reduced risk of breast cancer.

Turmeric is a yellow spice that has been reported to have anti-inflammatory properties and may limit the growth of breast cancer cells.

Maintaining a healthy body weight is important for well-being in general, and particularly for those engaged in the fight against breast cancer, because obesity is a known risk factor for the disease.

Being physically active is as important as eating healthful food for breast cancer prevention. The National Cancer Institute report that women who exercise for 4 hours per week or longer have a lower risk of breast cancer.